title: Metered dose inhaler: past, present, and future.
abstract: BACKGROUND
  The metered dose inhaler (MDI) to treat respiratory diseases was introduced many years ago. Due to the recently proposed ban on chlorofluorocarbon (Freon) production, the survival of the conventional MDI is uncertain. It is therefore incumbent on asthma caretakers to familiarize themselves with newer versions of the inhaler.
  
  
  OBJECTIVE
  To review the different modalities of aerosolized treatment employed in the management of asthma. This article is specifically focused on issues related to MDIs, the propellants, and the modifications since its introduction.
  
  
  METHODS
  The MEDLINE database was used to review MDI related literature in the English language.
  
  
  CONCLUSIONS
  Dry powder inhalers (especially the multi-dose type) and Freon-free pressurized MDIs appear promising and probably will replace conventional freon-propelled pressurized MDIs when Freon is no longer available.
authors.affiliation: The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Vaswani
authors.forename: P S
authors.initials: PS
authors.lastname: Creticos
mesh_terms: D000336:Aerosols / Q000008:administration & dosage*; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D001249:Asthma / Q000188:drug therapy*; D005544:Forecasting; D006801:Humans; D009330:Nebulizers and Vaporizers / Q000639:trends*
chemical_list: D000336:Aerosols; D018927:Anti-Asthmatic Agents